This whole discussion strikes me as rather chicken and the eggy because it seems highly unlikely to me that a man who doesn't suffer from ED could perform oral or manual on a woman to the point of orgasm and not become aroused himself unless he had recently ejaculated. If Karen's H suffers mainly from ED rather than lack of desire then IMO that is a different problem.
Also, I'm wondering why any woman should have to choose between the guy who gets an erection because he's hot for her form or the guy who is willing to give her pleasure even though he's not aroused. My personal preference would be for the guy who has integrated his sexuality to the extent that he can pat his head and rub my belly at the same time and I will gladly return the favor. GP and I were talking about this the other day and he said "Every man who isn't stupid wants a wife who's part slut."
"Tell me, what is it you plan to do with your one wild and precious life?" - Mary Oliver
